1. Field of the Invention
The invention discloses novel series of silicone polyesters which are useful as delivery systems for a variety of hydroxyl containing actives such as lanolin, cholesterol, dihydrocholesterol, Vitamin A, Vitamin D-2, Vitamin D-3, Vitamin D-4, Vitamin E, and Panthenol. Compounds of the invention are prepared by the esterification of (a) a hydroxyl containing silicone compound selected from silanol and dimethicone copolyol (b) a diacid and (c) a hydroxyl functional active and optionally (d) a mono functional fatty acid. The polyesters of the present invention allow for the formulation of personal care products in which the "active" can be formulated into a variety of solvents without the loss of activity.
By hydroxyl functional active is meant a vitamin, co-vitamin, or other material known to effect a change to the hair or skin which contains a hydroxyl group or hydroxyl groups.
2. Arts and Practices
The personal care market is a very diverse market segment which includes a number of products designed to be used on hair, skin, lips, and nails. These products include shampoos, bubble baths, pomades, conditioners, make up, hand creme, make up remover, hair relaxer, lipstick, nail polish, and many others. Some of these products are water based like shampoo others are mineral oil based like make up remover.
In addition to performing the specific cosmetic function in each type of product, there is a general need in each product type to incorporate ingredients which will help improve the condition of the hair, skin nails and lips. The desirable functions include but are not limited to; barrier properties, remoisturization, softening, and conditioning.
One of the most important function of human skin is the protection against adverse environmental factors. Environmental factors like exposure of the skin to sun, cold or heat adversely effects the skin and minimizes the barrier property of the skin. Additionally, the application of many cosmetic products or use of soap on the skin removes the fatty layer of the skin. It is therefore highly desirable to replace the barrier properties which are removed from the skin. Lipids and other oily materials added to the skin improve the natural barrier properties of the skin and hair the skin retain moisture and feel soft. If a suitable delivery system is used lanolin, cholesterol, dihydrocholesterol, Vitamin A, Vitamin D-2, Vitamin D-3, Vitamin D-4, Vitamin E, and Panthenol could be excellent materials for use as moisturizing and barrier creme applications. These materials are very difficult to deliver from aqueous environment. One attempt to deliver these materials to the skin has been to make emulsions of these oils in water. This is done by selecting surface active agents which will emulsify the hydroxy active into small droplets which are surrounded by the surface active agent in what are called micelles. The resulting emulsion resembles milk and contains the emulsified hydroxy active. The difficulty with this approach is that the material present in the micelle is deposited very inefficiently onto the hair and skin since the micelle must break to deliver the oil. Since the majority of the micelles do not break, the majority of the active is rinsed off and ends up in the drain. Another approach has been to make derivatives of these oily materials. Lanolin and cholesterol ethoxylates are commercially available which are water soluble. An example of this is lanolin with seventy five moles of ethylene oxide added. While the molecule is water soluble, the beneficial refatting effects are minimized. There has therefore been a long felt need for materials which could be incorporated into personal care products, which deliver the cholesterol or lanolin to the hair or skin in many different solvents, including water, mineral oil and others.
We have discovered that the incorporation of lanolin, cholesterol, dihydrocholesterol, Vitamin A, Vitamin D-2, Vitamin D-3, Vitamin D-4, Vitamin E, or Panthenol into a silicone polyester in relatively low concentrations results in polyesters which can be made soluble in many different solvents and which give the beneficial properties of the cholesterol or lanolin to the skin and hair. In short, low concentrations of these polyesters by virtue of their substantivity to hair and skin will provide outstanding remoisturization properties in many varied personal care formulations. Activity is seen at as low as 0.1%.
U.S. Pat. No. 5,051,489 issued September 1991 to O'Lenick teaches that silicone waxes can be prepared via esterification of silanol compounds. These materials contain no actives.
U.S. Pat. No. 5,100,956 issued March 1992 to O'Lenick teaches that silicone compounds can be linked to proteins or amino acids through a phosphate group. This invention shows the desirability of incorporating the active protein into a molecule containing silicone, which is one of the objectives of the current invention. The O'Lenick ('956) technology is not applicable to actives which do not have nitrogen in the molecule.